In recent years, there are an increasing number of mobile terminals such as mobile phones and PDA's (personal digital assistant) provided with a full browser. Accordingly, access to contents for PC's on a Web server as an information delivery server is expanding.
However, mobile terminals are often connected to a network through wireless communication and are generally more frequently disconnected than PC's connected to a network through wired communication.
Therefore, Japanese Patent Laid-Open No. 2005-316523 discusses a mobile terminal capable of browsing a content on a Web server off-line even if the connection to the network is interrupted. The technique capable of browsing a content on a Web server off-line even if the connection to the network is interrupted transfers the content on the Web server to the inside of a mobile terminal so that the content can be browsed even if the connection to the network is interrupted. However, the user of the mobile terminal needs to explicitly transfer the content on the Web server. Furthermore, even when the content on the Web server is updated, the user of the mobile terminal needs to explicitly transfer the content from the Web server to the mobile terminal again.
Japanese Patent Laid-Open No. 2002-149540 discusses a technique whereby a gate way (GW) server located between a mobile terminal and a Web server checks updates of a content on the Web server side and reports every update of the content to the mobile terminal. According to the technique, updates of the content on the Web server are checked page by page. However, such a page-by-page update check on the content on the Web server regards a change of an access counter whose contents are changed with every access or a change in an advertisement portion as an update.
A “hatena antenna” discusses a function that allows the user to set regions to be checked for updates and regions whose update checks are to be ignored. However, it is difficult to meticulously set regions to be checked for updates and regions whose update checks are to be ignored using a limited input interface of the mobile terminal.